Such a deflector is intended to be used for guiding a line moving in an installation, notably in an installation for laying or/and recovering a line. The installation is for example a laying vessel or an offshore platform able to lay a line in a body of water from the surface of the body of water. In other applications, the installation is in a shipyard or is located onshore.
The line moved in the installation is advantageously a flexible pipe, in particular an unbonded flexible pipe or a bonded flexible pipe. A flexible pipe is for example a pipe according to the standards API 17J (Specification for Unbonded Flexible Pipe) and API RP 17B (Recommended Practice for Flexible Pipe) established by the American Petroleum Institute. In a variant, the line moved in the installation is a rigid pipe, an umbilical, or a cable.
The laying of a pipe from a vessel generally implies guiding the pipe into the body of water from a laying tower located on the laying vessel. Generally, the pipe is passed on the laying tower, and guided into the water, either through a moon pool located at the center of the vessel (for example in J-lay method) or at the back of the vessel (for example in S-lay method).
The pipe needs to be accurately guided to ensure correct positioning when it enters the body of water, to warrant structural integrity of the pipe and/or to promote forced direction changing of the pipe.
Accordingly, deflectors have been widely used to guide pipes during laying operations. Some deflectors are fixed. Other deflectors comprise rollers or moving tracks.
In some cases, over bending of the pipe may occur at the deflector. In such occurrences, the force distribution applying on the pipe may concentrate on very limited regions of the pipe. This leads to an increase in the stress applied to the pipe, and may damage the pipe in case of excess friction. Such damages may irreversibly affect the pipe operation and shorten its service life.
U.S. Pat. No. 6,719,008 discloses an offshore loading system in which a pipe is suspended between two vessels. A deflector comprising a support, an intermediate member pivotally mounted on the support and a pair of rotating members each connected to a secondary pivoting member are supported on a cable. This assembly adapts to the shape of the cable. It nevertheless lacks robustness to be used as a deflector in a pipe laying installation.